1. Field of the Invention
Apparatuses and methods consistent with the present invention relate to an integrated circuit structure and fabricating the same, and more particularly, to an integrated circuit structure in which at least one Schottky diode and a capacitor are integrally realized and fabricating the same.
2. Description of the Related Art
With the recent development of wireless technology, wireless identification systems are used in a wide range of applications such as a simple prepayment bus card, an admission ticket for a parking place, and an entrance card of a research institute. Wireless identification systems basically perform their functions through exchange of radio frequency signals between a wireless identification tag and a reader unit. That is, when the tag transmits basic data required for identification to the reader unit, the reader unit receives and confirms the basic data. The tag may be manufactured in various forms such as cards, stickers, adhesive, etc., in accordance with the convenience of a user and the uses of the tag.
Wireless identification systems may be also applied for identification for articles in addition to identification for persons. That is, when an object having a tag is a person, basic data may include a name, date of birth, identity, qualification, etc. Further, when the object having the tag is an article, the basic data include a type, date of manufacture, manufacturer, place of origin, etc.
In the meantime, wireless identification systems may be classified into active wireless identification systems and passive wireless identification systems according to methods for operating an integrated circuit (IC) included in a tag. The active wireless identification system operates the IC by means of a battery included in the tag. The passive wireless identification system induces induced current by means of magnetic wave transmitted from a reader unit and operates the IC. In general, the passive wireless identification system is used because a light weight tag may be manufactured due to the non-existence of a battery.
FIG. 1 is a block diagram showing the general construction of a passive wireless identification system. Referring to FIG. 1, a passive wireless identification system includes a tag 10 and a reader unit 20. The tag 10 generally includes an antenna 11, a rectifier 12, a controller 13, a memory 14 and a transmission signal generator 15.
The antenna 11 may be constructed by a coil made from predetermined conductive material. Accordingly, when magnetic wave is received from the reader unit 20, the antenna 11 generates induced current according to Faraday's law. The generated induced current is converted into constant voltage having a predetermined size by the rectifier 12 and operates the controller 13.
The controller 13 extracts basic data stored in the memory 14. Then, the controller 13 controls the transmission signal generator 15 so as to modulate the basic data and generate radio frequency signals.
The generated radio frequency signals are transmitted to the reader unit 20 through the antenna 11. Accordingly, the reader unit 20 demodulates the received radio frequency signals and confirms the basic data.
In order to convert input signals induced in the antenna 11 into constant voltage, a rectifier may be constructed by means of a voltage doubler, etc. In such a case, when a general diode is used, detection efficiency for input signals having a low power deteriorates due to the high forward turn-on voltage of a p-n diode. In order to prevent the deterioration of such detection efficiency, research for using a Schottky diode having a low forward turn-on voltage has been actively pursued. In particular, for recent use in various industry fields such as a physical distribution transportation system, a wireless identification system operating in a high frequency band has been developed. In such a wireless identification system, it is general to fabricate a tag by means of a Schottky diode.
Further, when a rectifier is constructed by means of a plurality of Schottky diodes and capacitors, the rectifier has an increased area, so that the tag 10 has an increased size. Therefore, it is difficult to use the tag 10 in various industry fields. In addition, leakage current generates in a combination process between elements, so that voltage efficiency is reduced.